1/*
2 * Copyright (c) 1996, 2005, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package java.io;
27
28import java.util.Arrays;
29
30/**
31 * This class implements a character buffer that can be used as an Writer.
32 * The buffer automatically grows when data is written to the stream.  The data
33 * can be retrieved using toCharArray() and toString().
34 * <P>
35 * Note: Invoking close() on this class has no effect, and methods
36 * of this class can be called after the stream has closed
37 * without generating an IOException.
38 *
39 * @author      Herb Jellinek
40 * @since       JDK1.1
41 */
42public
43class CharArrayWriter extends Writer {
44    /**
45     * The buffer where data is stored.
46     */
47    protected char buf[];
48
49    /**
50     * The number of chars in the buffer.
51     */
52    protected int count;
53
54    /**
55     * Creates a new CharArrayWriter.
56     */
57    public CharArrayWriter() {
58        this(32);
59    }
60
61    /**
62     * Creates a new CharArrayWriter with the specified initial size.
63     *
64     * @param initialSize  an int specifying the initial buffer size.
65     * @exception IllegalArgumentException if initialSize is negative
66     */
67    public CharArrayWriter(int initialSize) {
68        if (initialSize < 0) {
69            throw new IllegalArgumentException("Negative initial size: "
70                                               + initialSize);
71        }
72        buf = new char[initialSize];
73    }
74
75    /**
76     * Writes a character to the buffer.
77     */
78    public void write(int c) {
79        synchronized (lock) {
80            int newcount = count + 1;
81            if (newcount > buf.length) {
82                buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
83            }
84            buf[count] = (char)c;
85            count = newcount;
86        }
87    }
88
89    /**
90     * Writes characters to the buffer.
91     * @param c the data to be written
92     * @param off       the start offset in the data
93     * @param len       the number of chars that are written
94     */
95    public void write(char c[], int off, int len) {
96        if ((off < 0) || (off > c.length) || (len < 0) ||
97            ((off + len) > c.length) || ((off + len) < 0)) {
98            throw new IndexOutOfBoundsException();
99        } else if (len == 0) {
100            return;
101        }
102        synchronized (lock) {
103            int newcount = count + len;
104            if (newcount > buf.length) {
105                buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
106            }
107            System.arraycopy(c, off, buf, count, len);
108            count = newcount;
109        }
110    }
111
112    /**
113     * Write a portion of a string to the buffer.
114     * @param  str  String to be written from
115     * @param  off  Offset from which to start reading characters
116     * @param  len  Number of characters to be written
117     */
118    public void write(String str, int off, int len) {
119        synchronized (lock) {
120            int newcount = count + len;
121            if (newcount > buf.length) {
122                buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
123            }
124            str.getChars(off, off + len, buf, count);
125            count = newcount;
126        }
127    }
128
129    /**
130     * Writes the contents of the buffer to another character stream.
131     *
132     * @param out       the output stream to write to
133     * @throws IOException If an I/O error occurs.
134     */
135    public void writeTo(Writer out) throws IOException {
136        synchronized (lock) {
137            out.write(buf, 0, count);
138        }
139    }
140
141    /**
142     * Appends the specified character sequence to this writer.
143     *
144     * <p> An invocation of this method of the form <tt>out.append(csq)</tt>
145     * behaves in exactly the same way as the invocation
146     *
147     * <pre>
148     *     out.write(csq.toString()) </pre>
149     *
150     * <p> Depending on the specification of <tt>toString</tt> for the
151     * character sequence <tt>csq</tt>, the entire sequence may not be
152     * appended. For instance, invoking the <tt>toString</tt> method of a
153     * character buffer will return a subsequence whose content depends upon
154     * the buffer's position and limit.
155     *
156     * @param  csq
157     *         The character sequence to append.  If <tt>csq</tt> is
158     *         <tt>null</tt>, then the four characters <tt>"null"</tt> are
159     *         appended to this writer.
160     *
161     * @return  This writer
162     *
163     * @since  1.5
164     */
165    public CharArrayWriter append(CharSequence csq) {
166        String s = (csq == null ? "null" : csq.toString());
167        write(s, 0, s.length());
168        return this;
169    }
170
171    /**
172     * Appends a subsequence of the specified character sequence to this writer.
173     *
174     * <p> An invocation of this method of the form <tt>out.append(csq, start,
175     * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
176     * exactly the same way as the invocation
177     *
178     * <pre>
179     *     out.write(csq.subSequence(start, end).toString()) </pre>
180     *
181     * @param  csq
182     *         The character sequence from which a subsequence will be
183     *         appended.  If <tt>csq</tt> is <tt>null</tt>, then characters
184     *         will be appended as if <tt>csq</tt> contained the four
185     *         characters <tt>"null"</tt>.
186     *
187     * @param  start
188     *         The index of the first character in the subsequence
189     *
190     * @param  end
191     *         The index of the character following the last character in the
192     *         subsequence
193     *
194     * @return  This writer
195     *
196     * @throws  IndexOutOfBoundsException
197     *          If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
198     *          is greater than <tt>end</tt>, or <tt>end</tt> is greater than
199     *          <tt>csq.length()</tt>
200     *
201     * @since  1.5
202     */
203    public CharArrayWriter append(CharSequence csq, int start, int end) {
204        String s = (csq == null ? "null" : csq).subSequence(start, end).toString();
205        write(s, 0, s.length());
206        return this;
207    }
208
209    /**
210     * Appends the specified character to this writer.
211     *
212     * <p> An invocation of this method of the form <tt>out.append(c)</tt>
213     * behaves in exactly the same way as the invocation
214     *
215     * <pre>
216     *     out.write(c) </pre>
217     *
218     * @param  c
219     *         The 16-bit character to append
220     *
221     * @return  This writer
222     *
223     * @since 1.5
224     */
225    public CharArrayWriter append(char c) {
226        write(c);
227        return this;
228    }
229
230    /**
231     * Resets the buffer so that you can use it again without
232     * throwing away the already allocated buffer.
233     */
234    public void reset() {
235        count = 0;
236    }
237
238    /**
239     * Returns a copy of the input data.
240     *
241     * @return an array of chars copied from the input data.
242     */
243    public char toCharArray()[] {
244        synchronized (lock) {
245            return Arrays.copyOf(buf, count);
246        }
247    }
248
249    /**
250     * Returns the current size of the buffer.
251     *
252     * @return an int representing the current size of the buffer.
253     */
254    public int size() {
255        return count;
256    }
257
258    /**
259     * Converts input data to a string.
260     * @return the string.
261     */
262    public String toString() {
263        synchronized (lock) {
264            return new String(buf, 0, count);
265        }
266    }
267
268    /**
269     * Flush the stream.
270     */
271    public void flush() { }
272
273    /**
274     * Close the stream.  This method does not release the buffer, since its
275     * contents might still be required. Note: Invoking this method in this class
276     * will have no effect.
277     */
278    public void close() { }
279
280}
281